1. Field of the Invention
The present invention relates to ion implantation, and more particularly, to an ion implantation method and an ion implantation apparatus.
2. Description of the Related Art
In semiconductor manufacturing processes, a process for implanting ions into a semiconductor wafer is performed in a standard procedure for the purpose of changing conductivity, changing a crystalline structure of the semiconductor wafer, or the like. An apparatus used in this process is generally called an ion implantation apparatus.
The ion implantation apparatus is configured so that, for example, an ion source, an extraction electrode, a mass analysis magnet device, a mass analysis slit, an acceleration/deceleration device, a wafer processing chamber, and the like are arranged along a beamline so as to implant ions into a wafer which is a semiconductor substrate.
In general, since the cross-sectional area of an ion beam with which a wafer is irradiated is smaller than the size of the wafer, several irradiation methods for irradiating the entire surface of the wafer with the ion beam have been contrived. As an example of the irradiation method, there is a known method of performing ion implantation on the entire surface of the wafer by scanning the wafer with an ion beam in one direction and allowing the wafer to be reciprocally scanned in the direction perpendicular to the ion beam scanning direction.
In addition, as one of means for controlling an implantation dose in an ion implantation area, there is a contrived ion implantation apparatus where a plurality of ion beam detectors performing current detection in an X-direction (ion beam scanning direction) are installed behind a platen mounting wafers and an automatic X-scanning width controller automatically controlling an X-scanning width and an automatic Y-scanning speed controller automatically controlling a Y-scanning speed (wafer movement speed) are included.
In addition, similarly, as another means for controlling an implantation dose in an ion implantation area, there is a contrived method of measuring a beam current amount during ion implantation and automatically correcting and tracking a Y-direction (wafer movement direction) speed of a mechanical scanning device based on the measured beam current amount.